


Lost to Instinct

by thewinchesterlifestyle



Category: Supernatural
Genre: Alpha Dean, Alpha/Beta/Omega Dynamics, Alpha/Omega, Alternate Universe - Canon Divergence, Angel Dean Winchester, Angel Mating, Angel Wings, Angelic Grace, Barebacking, Bottom Castiel, Breeding, Butt Plugs, Come Inflation, Grace Sex, Grace Sharing, Hunter Castiel, Knotting, M/M, Marathon Sex, Mating Cycles/In Heat, Mating Season, Mpreg, Nephilim, Omega Castiel, Outdoor Sex, Past Castiel/Other(s), Pheromones, Pregnant Castiel, Protective Dean, Righteous Man Castiel, Rimming, Rough Sex, Sigils, Size Kink, Top Dean, Unplanned Pregnancy, breeding talk, reverse verse, season five AU
Language: English
Status: Completed
Published: 2017-06-15
Updated: 2017-06-15
Packaged: 2018-11-14 15:24:11
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 5,422
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11210856
Author URL: https://archiveofourown.org/users/thewinchesterlifestyle/pseuds/thewinchesterlifestyle
Summary: Castiel froze when he heard the low rumble Dean released and saw the almost predatory look that took over Dean's handsome face. He had never been more aware that Dean was anAlpha angelthen he was in that moment.





	Lost to Instinct

Castiel laid sprawled out in bed, body tired and aching after taking down a nest of vampires. He kept blinking, jerking slightly as his body fought against sinking into sleep, until Castiel couldn’t keep his eyes open anymore. Slowly sleep started to drag him into blissful unconsciousness.

His muscles relaxed, his body sank into the cheap mattress of the room he’d barely managed to rent for the night and his mind drifted.

The sound of wings had him jerking up in bed.

“Dean?” Castiel’s voice was rough, scratchy almost, as he blinked in the darkness and could barely make out the outline of his angel standing at the foot of his bed. “Is everything alright?”

There was a low sound and Castiel tensed. He could feel Dean’s eyes staring at him but the typically talkative angel wasn’t saying a word. Without pulling his eyes from the dark shape he leaned over and turned the lamp on.

Light flooded the room and Castiel stared.

Dean’s cheeks were flushed, his body trembling finely and he could _see_ the angel’s tawny wings arched high. Something was very clearly wrong and as he stared he watched as Dean’s grace seemed to flare in his eyes.

He didn’t hesitate. Castiel tossed his covers back, not caring about his state of undress, as he closed the distance. Concern flooded him. Something had to be wrong but he couldn’t see any surface injuries. Castiel’s hand landed on Dean’s shoulder and he could feel the tension radiating through Dean’s body.

“Dean…what’s the matter?”

Sharp eyes tracked every single movement he made, Dean appearing to be hyper-aware and on edge, as Castiel watched him swallow roughly. He could see Dean fighting something, poised almost as though he was about to fly away or lunge forward.

“Dean.”

Dean started scenting the air. Castiel froze when he heard the low rumble Dean released and saw the almost predatory look that took over Dean's handsome face. He had never been more aware that Dean was an _Alpha angel_ then he was in that moment.

Dean’s wings shifted, drawing Castiel’s attention as he took in the gorgeous display, and a heady, tantalizing scent filled his senses.

Alpha pheromones

“Oh.” Castiel’s cheeks warmed as Dean’s scent, usually so carefully hidden and controlled, suddenly started to flood the room. It was mixed with the scent of arousal, sex and scents that seemed to belong to other Omegas. “Dean…”

Dean prowled forward, wings arched up, as his eyes took in Castiel’s very undressed form and fixed on the hand-print that had been burned into him from the moment Dean had hauled him out of Hell.

“Cas.” It was the first thing Dean had managed, “You smell…so good.” his angel’s eyes were hooded and freckled cheeks were darkly flushed.

“Dean…are you going into a Rut?” Castiel’s voice was not steady and he was doing everything not to whine at how good Dean smelled, how tempting his angel was. He was more than sure humans were _not_ supposed to have sex with angels.

Dean shook his head but never looked away as he crowded close and leaned in to breathe in Castiel’s scent. A low rumble escaped and even more pheromones filled the air. Castiel’s head spun and his cheeks flushed darkly, mouth parting on a soft moan. “No.” Dean managed, fingers touching his mark on Castiel’s shoulder. “It’s mating season.”

Castiel blinked through the haze of arousal flooding his mind and body.

“Mating season?”

“Yeah.” Dean breathed as his wings arched again in a very clear dominate display now that Castiel was paying attention. “Mating season. I should still be in Heaven, catching and breeding Omega angels like I do every season but…” he trailed off and Castiel could see him struggling for control.

“But?”

“No matter how many Omega angels I caught and knotted I couldn’t get _you_ out of my head.” Dean looked pissed at himself and Castiel stared. “I kept imagining the Omega pinned under me was _you_ and I want…”

_Bad idea. This is a very, very bad idea._

Castiel carefully, deliberately, offered his neck and lowered his eyes in submission like a good Omega was supposed to. Dean’s eyes glowed with grace and his wings snapped up. The pheromones from before were nothing compared to the ones that now saturated the air and sunk in to Castiel like fangs.

He barely kept his feet as a broken whine escaped him.

Dean’s hands curled around him and Castiel felt the rush of flight as they disappeared from his cheap room. He had a moment to feel relief at paying for the week as they landed in a clear, open field.

His boxers were gone in one second and Dean’s clothing in the next as the Alpha angel advanced on him. Castiel wasn’t exactly sure how angel mating season went but he had no problem letting Dean haul him to the soft grass.

Castiel was pressed down, knees sinking into the ground, as Dean knocked them apart and jerked his hips up in the Alpha favored position meant for mounting. His cheek pressed against the grass and his fingers dug in as a warm tongue dragged right over his slick cunt up to his tight hole.

He jerked, a sharp and startled moan escaping, when Dean’s tongue moved back down to lap at his cunt until he was almost sobbing with need and trembling at the warmth curling in his gut as Dean dragged him towards an orgasm with only his mouth.

“Fuck, Cas.” Dean’s voice sounded wrecked, “You taste so good. So fucking good.” fingers dipped into his cunt, twisting and fucking, causing Castiel to push back into Dean’s touch as he tried fucking himself on Dean’s fingers. It had been weeks since he’d had sex, weeks since he had allowed himself the pleasure of a strong Alpha fucking him into the mattress, but there was something more about it being Dean behind him.

His angel.

“Please.” He sounded just as wrecked as Dean, “Please Dean…please _Alpha_.”

A snarl escaped Dean at the word and Castiel could feel his slick leaking out of his loosened and thoroughly soaked cunt. Castiel didn’t have to wait long before the wide head of Dean’s cock pushed against his cunt and started to sink in.

He could practically feel how Dean was forcing himself not to slam inside, no doubt able to give in to his full power with Omega angels but mindful of Castiel’s unfortunately fragile humanity. Castiel shoved back into him, coaxing and whining, until warm balls pressed up against him and Dean’s entire thick cock was inside of him.

Castiel regretted not seeing Dean completely naked before this point. He’d been fucked and knotted by plenty of Alphas since he had presented, an Alpha had wasted little time in relieving him of his virginity regardless of his young age when he’d presented in public, but Dean felt gigantic filling his cunt compared to all of those other Alphas save that first one who had broken in his young body. It ached where he was stretched and filled more than he was used to but as Dean rolled his hips back and fucked back into him those thoughts slipped away.

Dean had nailed his sweet spot and as strong, capable hands gripped his hips and Dean started to vigorously fuck into him it became obvious that Dean was managing to nail that spot every single time on purpose.

Bliss and warmth and pleasure burned inside of him as Castiel moaned loudly. It echoed into the darkness of the clearing. He could feel how Dean’s fingers threatened to dig harshly into his hips but his angel, in the midst of mating season, was showing remarkable control compared to human Alphas lost to Rut.

The sound of skin smacking skin filled the clearing along with Dean’s pleasured grunts and moans as his angel rapidly started to pound into his cunt and Castiel could only grip the grass as his body swayed from the force.

“Alpha ohhhh ohh fu—please there yes yes yes.” Castiel’s mind floated on pure, unrelenting pleasure while Dean’s pace picked up and his angel never once missed his prostate. His orgasm caught him by surprise; Castiel had never come in the middle of being fucked without additional stimulation. “ _Ohhhhhh_.”

His body went pliant underneath Dean, warm and well fucked, as his orgasm buzzed inside of him and each thrust of Dean inside of him sent even more pleasure zipping through his sensitive body.

Powerful fingers flexed where they were dug into his hips and Castiel shuddered as Dean’s pace picked up, greedily rutting against his cunt, until the angel’s growing knot pressed inside. It sunk into his cunt and swelled, pushing and spreading his inner walls open, until Dean was locked inside of him.

The warmth of Dean’s grace, usually only felt when his angel healed him, wrapped around him and a second orgasm had Castiel sobbing out. His muscles trembled even as his inner muscles viciously clamped down on Dean’s knot to start milking it.

Behind him Dean groaned, rocking up against him, as his warm body draped over Castiel’s and effortlessly pinned him to the ground. One of the warm hands at his hip drifted down, curving over his flat belly. He could hear Dean practically purring with satisfaction, the rumble vibrating against his back, as Dean ground up against him and warmth flooded him each time Dean’s release poured into him.

“Want to breed you.” Dean breathed out, voice sounding practically scent drunk and wrecked with delight, as he continued rocking up against Castiel and Castiel whined lowly when Dean’s knot brushed his sweet spot. “Going to fill you up with fledglings.” Grace continued to lazily twine through him. “Fill your womb.”

Castiel’s cheeks flushed and his mouth fell open on a gasp when Dean’s grace seemed to sink into him completely. He could feel soft, warm wings brushing against his naked body and hear Dean’s continued breeding talk.

“Mmmmm.” Dean hauled him up so he was up on his knees and completely pressed along the length of Dean’s body. It had Dean’s knot tugging on his aching cunt and a whine escaped as Dean nuzzled against the spot where his bonding gland was located. “Smell so good, Cas. Gonna smell better when you’re bred.”

Dean still sounded a bit scent drunk.

“You’re so good for me, Cas. Such a good Omega.” A hand continued to stroke at the place where his belly would start to swell if Castiel was properly bred. “Wish you could fly so I could catch you. Fuck and knot you in midair. You would make a beautiful Omega angel.”

Dean continued to nuzzle against his bonding gland, releasing pleased sounds, even as his knot emptied load after load into Castiel fucked out body. He ended up a limp, fucked out mess on the grass when Dean teased him with his grace to a third orgasm and five minutes later his knot slipped free.

Castiel panted, cunt still raised up in offering and knees bent, as Dean’s fingers pushed his escaping release back inside of Castiel. “You smell like me.” The tone was pleased and Castiel could see Dean’s grace still glowing in his eyes when he managed to glance back.

It was similar to seeing an Alpha’s eyes glow red when they were lost to a Rut or giving over to their instincts. It made him want to offer his neck, again. “How… _ohhhh_ …how long does mating season— _fuck Dean_ —last?”

“Two weeks.” Dean’s other hand had reached under to rub against Castiel’s tiny cock, fingers occasionally rubbing the empty spot between his cock and cunt, before his other hand fingered his fucked open cunt. “I managed to last a week before I couldn’t keep you out of my head. Kept imagining your scent while I was breeding other Omegas.”

A week.

Castiel groaned at the thought of _that_ for a whole week and wasn’t sure his body could stand the kind of fucking required for an Alpha angel during mating season. “You already spent a week of your mating season and you’re still like this?”

He went to open his mouth to ask something else but the sensation of Dean sheathing himself back inside of his cunt stole the words right out of Castiel’s mouth. Castiel went from fucked open and empty to fucked full of a very impressive Alpha angel cock that was already hard again.

“Ohhhhhh.” His eyes hooded and his lips parted as he moaned lowly.

Fingers curled around the back of his neck causing him to go pliant and submissive, whining brokenly, as Dean started to fuck him harshly into the ground. He ached and burned, trembling and releasing more whines, as Dean roughly pounded into him.

Heavy balls slapped against his ass and the wet, sucking sound of a large cock plowing through a soaked cunt filled the air along with more of Dean’s pleasured sounds. “Good Omega.” Dean’s voice was rougher, “So good at taking my cock and knot. Going to fuck you full. Breed you with fledglings.”

Castiel stared unseeingly out at the dark clearing as Dean continued fucking him and grace once more started to thread through his body, lighting him up with pleasure and unspeakable bliss. He came with a silent cry, body tensing and locking down on Dean’s cock, as Dean fucked him through it and kept snapping his hips forward until he was shoving his knot inside Castiel once more.

“Alpha Alpha Alpha.” Castiel trembled and panted, body singing and muscles lax underneath Dean. “Ohhhh. Dean… _please_.”

“So good. So bright. Such a bright soul, Cas. Beautiful.” Dean’s voice sounded far away and Castiel whined when Dean’s warm grace kept twining through him. “I got you, Cas, I’ll take good care of you.” He ground forward against Castiel as warmth continued to flood Castiel’s cunt, “I’m going to fuck you till you’re swollen and limp.”

Castiel distantly thought Dean had already gotten one out of two. He didn’t think he could stand if his life depended on it. The constant stimulation of Dean’s grace, the vigorous sex and the lingering exhaustion from his most recent hunt had him only able to lie there as Dean sated his instincts.

“Shhhhh.” A warm hand stroked the slope of his back, almost as though Dean was petting him, “I’ll take care of you.” It was nice to know in the middle of a mating season that this particular Alpha angel was not only focused on breeding but on taking care of the Omega he was fucking.

He drifted to the feeling of Dean stroking him, murmuring promises of fledglings and care, and the flood of warmth inside of him with each orgasm.

When Castiel woke up he was on his belly, body fucked loose and Dean was rutting his knot into Castiel’s cunt once more. He could see the sun in the sky, feel the warmth on his pliant body and see the shadows of Dean’s wings on the grass.

He whined softly when Dean’s knot slipped into his thoroughly fucked and used cunt. Castiel felt fuzzy, well fucked and warm.

Dean draped over him, lazily fucking his knot up against Castiel, while the sound that reminded Castiel of a purr signaled how pleased Dean was as he emptied his release into Castiel. Lips pressed right against his bonding gland and a sudden, familiar warmth surged through his entire body. Every ache and pain was washed away, his exhaustion leached from his bones and Castiel suddenly felt completely alert.

“Slept for nine hours.” Dean mumbled against him, “Thought I’d let you rest. I kept you under while I bred you. You needed some rest.”

That explained the very thoroughly fucked feeling he’d woken up with. If an angel mating season put an Alpha angel into such a frenzy it wasn’t a leap to guess that Dean had kept fucking and knotting him just as a human Alpha in Rut would do. 

“Don’t know how I’m going to survive a week of this.” Castiel admitted as Dean’s knot dragged across his sweet spot and he whined lowly where he was pinned down on the same soft grass.

“Grace.” Dean lazily kept rolling his hips forward, moaning in enjoyment as Castiel’s inner muscles milked his knot. “I’ll sustain you and help you keep up.”

It was a week of nonstop fucking. He was going to be useless after this. Completely, undeniably useless. Castiel figured he might need a week of sleep after week long marathon sex with an insatiable Alpha angel finishing off mating season. It seemed impossible to think that angels had a two-week long mating season when five days was more than enough for him during a Heat.

Castiel could feel Dean’s lips and tongue grazing the sensitive skin over his bonding gland but teeth never bit down. Hours and hours, days and days, of fucking and knotting and breeding talk but Dean _never_ claimed him.

They had hardly moved from that spot in the middle of nowhere, exposed to nature and completely naked the entire time, as Dean repeatedly and enthusiastically fucked his way through the second half of angel mating season quite happily focusing all of his attention on Castiel.

On day seven Castiel could only lie there, belly bulging with near seven days’ worth of Dean knotting him and a grace provided plug locking it all up inside of his cunt. His skin was tanner than usual and he knew he should feel filthy but Dean had been true to his word.

His grace had taken care of _everything_.

Castiel hadn’t needed to eat, drink, bathe or take care of any basic human need. The only thing he’d had to do was present and offer his cunt for Dean’s use. He idly glanced over at where Dean was sitting a few feet from him, a very pleased and smug air about him, as he languidly groomed his feathers.

He watched how the sunlight played over Dean’s handsome features and how it lit up the tawny feathers so they almost seemed golden. Dean was completely uncaring of his nudity and there wasn’t a single sign of the near out of control Alpha instincts that Castiel had seen for a week. Dean was languid and content.

The warmth of the sun had him lazily relaxing on the grass, curled on his side and body completely limp. He had only briefly glanced at the unnatural swell of his stomach, an impossible amount of come locked inside of him that should have come from a huge group of Alphas instead of one, before he’d found himself watching Dean’s easy movements.

There wasn’t a sign that Dean had spent two weeks breeding Omegas, one in Heaven and one on Earth getting lost in Castiel’s body.

It wasn’t fair how angels seemed so little effected.

“You can sleep, Cas.” Dean spoke as he turned to his right wing, fixing feathers and using his wing oil to groom them. “I’ll watch over you.”

Castiel didn’t want to sleep but as he watched Dean, listening to his angel humming while he groomed his wings, Castiel found that he couldn’t quite keep his eyes open. He blinked and each time it seemed harder to open his eyes again.

He came awake wrapped up in warm sheets in a darkened room. The aches and slight pains were gone. He _felt_ clean and refreshed but a slight shift let him know he still had a plug caught in his cunt and a hand moving down revealed the bulge of Dean’s come was still locked inside of him.

For the first time since it all started, since he gave in to his selfish want and Dean’s obvious need, Castiel realized that Dean’s breeding talk might not have just been talk. He blinked in the darkened room and moved his hand over the swell of his belly that was simply seven days of come.

But would it be… _fledglings_ after enough months passed?

Castiel sat up and groaned as he clenched down on the thick plug. He turned on the light to get a good look at the room that Dean had taken him from. “Dean?” he asked the empty room. Castiel waited and waited but there wasn’t a sign of his angel. “ _Dean_.” He tried again and focused on sending along the call in a prayer.

The sound of wings had him opening his eyes and he took in Dean’s form standing at the foot of his bed. “Hey Cas.” Dean wouldn’t meet his eyes and Castiel frowned. He missed the sight of Dean’s wings and the usual look of cocky assurance even as the outfit was completely familiar.

“Did something happen?”

“No…” he trailed off and walked towards the window, gazing out into the darkness while Castiel stared at him trying to fathom what was going on with Dean.

Castiel tried to figure out how to word his question without possibly offending the angel standing before him. “Did…did I do something?” it was a good question and a possible lead in.

Dean’s head snapped up and he shook his head. “No, Cas. You didn’t do anything.” A humorless chuckle escaped Dean, “I did.”

“You were fine when I saw you last in the clearing.”

There was an obvious flush across Dean’s freckled cheeks and Castiel stared. “That…that was a post-mating season high.” Dean twitched and Castiel watched him seem to decide something. “It’s an Alpha thing…I knew I had fathered fledglings. It’s a pride kind of thing. I can’t help it.” The last part sounded mildly defensive. "Alpha angels are compelled to father countless fledglings with as many Omegas as possible."

“With one of the Omegas during the first half?” he asked not quite ready to ask about himself but if Dean said no then that would be answer enough. Castiel waited as Dean sighed.

“Ten, actually.” Dean finally responded, “I managed to breed ten Omegas before I came to Earth.” There was undeniable pride in Dean’s tone, the tone all Alphas had when they had managed to breed an Omega. It was a sign of their virility and prowess. “Omega angels are typically bred by several Alphas during mating season but I managed ten successful breedings before I left for Earth. Ten out of the twenty eight Omegas I coupled with. It was an average mating season.”

Castiel swallowed at the knowledge that in the week Dean had been spending mating season with actual Omega angels he’d bred _ten_ of them. “That’s great.” He offered a small smile. Dean would be a good father to a bunch of fledglings. “Are these the first or…”

“No.” Dean shook his head, “I’ve fathered a lot of fledglings over the millennia since I was created.” That made complete sense. There had probably been more mating seasons than Castiel could imagine. “I had never fathered Nephilim.”

The product of an angelic parent and a human.

Castiel froze as he watched Dean offer him a humorless smile. He could see guilt warring with pleasure in Dean’s beautiful green eyes as they regarded him. “I’m so sorry, Cas.” Dean sat down on the edge of the bed and his eyes flicked to Castiel’s round belly still holding the evidence of Dean’s efforts during mating season. “I…I lost control and I shouldn’t have done that to you. I should have _never_ come to Earth. I took advantage and—”

“You didn’t take advantage of me.” Castiel protested immediately even as his mind numbed at the realization he was carrying Nephilim. Dean _had_ successfully bred him. “It’s…it’s going to be fine, Dean.”

“I’m just lucky that as an archangel’s vessel you were created to hold _Michael_ and that carrying Nephilim won’t cost you your life otherwise this would be a death sentence one way or another.” Dean’s lips twisted, “Or I could…” he trailed off and raised his hand, palm glowing softly, and Castiel watched something pained in Dean’s eyes appear briefly before disappearing. “They’re considered abominations…”

Castiel jerked and shifted back, arms curling around his stomach protectively, as he moved to shield himself instinctively. “No!” even if he hadn’t planned on having children or being bred he couldn’t do that.

Not for the life he carried, himself or the pain in Dean’s eyes. Castiel could be greedy and he didn’t want to give up something his angel had given him.

“You can’t do that, Dean. You can’t just…kill—” he shook his head, “Please don’t.” it didn’t matter that he’d just found out he was _pregnant_ and he was carrying _Nephilim_ because the very thought of it was painful.

He was carrying something that was half Dean and half him. It could have been one of the numerous Alphas he'd let fuck and knot him but it was an Alpha he actually knew who had fathered his child. He couldn't possibly let Dean kill it.

“It would be easier.” Dean murmured without conviction or strength. “They’re not supposed to exist…I should have never placed you in such a position but I don’t always think rationally in the middle of mating season. It didn't help that I've been around you enough that your scent was practically clinging to me.”

The admission was filled with guilt and Castiel moved closer to Dean. “You didn’t force me to do anything I didn’t want or enjoy.” He gripped Dean’s wrist and watched as his angel stared at him. “It’s going to be fine. The world might be ending but it’s going to be fine.”

Probably not.

Dean huffed out a humorless laugh, “If Michael doesn’t wipe me off the face of the Earth.” His lips twisted into a wiry grin, “I _ruined_ his True vessel. Being one of Michael’s favorites isn’t going to save me from the consequences of _that_.”

Castiel blinked and flushed as Dean’s fingers idly ghosted over his belly. “I’ve had sex before, Dean. It isn’t like you took my virginity. I haven’t been pure in a very, very long time. I've been fucked and knotted by more Alphas then I can even remember.”

“Technically when I recreated your body and placed you back on Earth you were completely pure again.” Dean’s lips twitched, “That lasted…what? Three days?” Castiel flushed at the memory of getting drunk and letting a very burly Alpha take him back to his house to spend an entire night fucking Castiel into the mattress. He'd then spent his first Heat, pissed at his brother, at an Alpha bar getting gangbanged. The only reason he had any memory of it was because someone had filmed it and posted it online where he found it on a porn site.

Dean’s fingers continued to move over his belly. Castiel’s cunt clenched as the memory of Dean’s warm hand curved against the growing swell as he’d greedily fucked Castiel’s cunt while growling out promises of breeding and fledglings flashed through his mind.

“I _bred_ you, Cas.” Dean pointed out after a moment, “That’s how I ruined you.” His hand retreated, “If anyone was to breed you it would have only been Michael. No other should have touched you in such a way because you were meant for Michael only. Now you’re carrying Nephilim created with another angel’s grace, my grace.”

Castiel scowled, “I’m not meant for _anyone_. I’m not property.” He hated that. It was a very common thought process among Alphas and society firmly taught it as fact. He didn’t mind sex, loved being manhandled and fucked roughly, but he didn’t like the facts about how Omegas were considered property. “I have no intention of letting him breed me.”

“Which is another reason he’ll want to make an example of me, no doubt. He'll see it as a challenge and if I'm lucky, if we're both lucky, he'll merely make sure to breed you full of his fledglings in an effort to reclaim what he considers his.” Dean looked up, grimaced and then looked back at Castiel. “I’m going to try to hide them as best I can. Their grace is very faint and with mating season just finishing no one should have noticed yet. He might not kill me for this but it certainly isn’t going to end well for me.”

Castiel was waved off when he started to protest Dean’s offhanded comment about being punished for breeding him.

Dean’s hand rested on Castiel’s stomach and in a warm flash Castiel jerked slightly at a dull feeling of pain inside of him. “What was that?”

“I warded your womb.” Dean pulled his hand back, “It’s similar to the warding and sigils on your bones only this is meant to hide what is growing inside of you. It was commonly used when Nephilim were accidentally created centuries ago.” He stood up and moved away from the bed. “I’ll be back as soon as I can, Cas. I won’t…I won’t leave you to this alone.”

Relief was a heady thing and had him slumping back against the headboard. Despite Dean having bred multiple Omega angels and breaking a taboo of Heaven he was still going to help. He wasn’t going to leave him alone. It was a relief.

_You saw him in that world Zachariah showed you. Even a shell of himself and he was with you till the very end. He wouldn’t leave you over this._

“Thank you, Dean.” Castiel breathed. He paused and thought about how Dean constantly touched his bonding gland but never broke it. “Is that why…?”

“Why I didn’t break your bonding gland?” Dean arched a brow and a knowing look stole over his face. “That _isn’t_ for me, Cas. I can’t give you what a human Alpha could and the target it would paint on you would be enormous. Despite the Nephilim you deserve a human Alpha to claim you and give you babies that won’t be considered abominations.”

Castiel ignored the short spike of pain at Dean’s words.

“Besides I’ve already technically marked you…illegally might I add.” Dean jerked his head in the direction of the evidence that he had been the one to save Castiel from Hell. “I gripped you a little too tightly. I burned my mark into your very soul, Cas. No one was happy about that. It was like screaming **mine** at everything in the universe.”

Dean’s hand moved up to brush against the mark, “Ok.” It was the only thing Castiel could think of. Dean offered a small, reassuring smile and a soft _bye Cas_ before he was gone and Castiel was alone again.

It took him twenty minutes to get up, stumble into the bathroom and start cleaning up. Dean had left him a mess, a very thoroughly fucked mess, and Castiel had found himself flushed with embarrassment at the evidence of how he’d spent seven days.

Seven days of pleasure instead of seven days fighting, saving people or trying to prevent the end of the world. And now he was pregnant with Dean’s fledglings. Pregnant with _Nephilim_. “Righteous Man indeed.” He muttered as he stared at himself in the mirror with steam from his hot shower curling in the bathroom.

Bright blue eyes stared back at him from the mirror set on a flushed face. He looked away and down, taking in his now flat stomach, as his mind easily offered him the image of himself swollen with the Nephilim Dean had bred him with. He thought of his brother and knew it would only be a secret until he started to show. That was going to be a fun conversation and Castiel was going to put it off for as long as he could manage.

The first thing he needed to do was cover up the fact that Dean had bred him. If the angels were occupied by mating season they wouldn't be now and he knew they were watching him. Castiel made sure he was cleaned thoroughly, dressed in clothing he didn't give a fuck about and grabbed a plug. There was a very busy Alpha bar nearby and he was sure letting himself spent a night being repeatedly knotted by a bunch of horny Alphas would make the angels thing one of them were the father of the Nephilim that would soon cause his belly to swell.

It would give him a bit of extra protection when the angels noticed his bred womb.

**Author's Note:**

> I wanted another chance to play around with my little headcanon that vessels for archangels could successfully carry Nephilim. Also I really loved the idea of Dean spending mating season as he usually does, breeding as many Omegas as he could, but he just felt compelled to breed Castiel as well and he ends up getting carried away with the high of mating season (and actually does breed Cas). There were accidental hints of plot and I don't know how that happened...
> 
> It's a little different, set in canon but not. I don't really write the reverse verse but I'm hoping this one at least came off mildly entertaining...guess I shall know soon enough by your responses.
> 
> Let me know what you thought of this one! It's one of my favorites (I have far too many favorites but then again...I've written far too many fics).
> 
>  
> 
> I'm also tentatively going to try to accept some prompts for _bottom!Cas fics_ since I've noticed most of my fics lean towards bottom!Dean. You can submit a prompt [ here](https://surveynuts.com/surveys/take?id=167280&c=4743391697PLTD).


End file.
